1. Field
The disclosed and claimed concept relates generally to an electrical switching apparatus and, more particularly, to an arc extinction apparatus for a DC switch apparatus.
2. Related Art
Numerous types of circuit interrupters are known for use in diverse applications. In certain applications, such as low power situations, the circuit interrupter can be as simple as a mechanical switch, of which many types are known.
One type of mechanical switch that is employed in somewhat higher voltage and current applications involves the use of a rotatable shaft upon which an elongated conductor is mounted. The ends of the conductor are electrically connected with a pair of contacts when the circuit interrupter is in an ON condition. When the circuit interrupter is moved toward its OFF condition, the shaft is rotated, which causes the elongated conductor to pivot about the pivot axis about the shaft, which causes air gaps to form between the ends of the elongated conductor and the pair of contacts. While such circuit interrupters have been generally effective for their intended purposes, they have not been without limitation.
Certain applications involve DC circuits, and it has become desirable in certain applications, such as photovoltaic applications, to increase the voltage and current flowing within a circuit, which consequently increases the difficulty of extinguishing arcs that form at the air gaps when switching a circuit interrupter from an ON condition to an OFF condition. For example, it has become desirable in photovoltaic applications to increase the number of solar arrays arranged in parallel and in series which increases current and voltage, respectively, which must be interrupted by a circuit interrupter. Moreover, depending upon the orientation of the contacts in relation to one another and in relation to the elongated conductor, it is possible that the arc created at the air gap can tend to move along the elongated conductor toward the pivot axis of the shaft. Movement of the arc toward the pivot axis of the shaft on which the elongated conductor is mounted tends to shorten the arc and to reinforce it, which is undesirable since any arc is preferably extinguished as soon as possible. While efforts have been made to employ magnets in extinguishing arcs in such circuit interrupters, the result has been a circuit interrupter that can only interrupt DC power in a given polarity. That is, such a circuit interrupter cannot interrupt DC current flowing in an opposite direction with reverse polarity through the circuit interrupter. It thus would be desirable to provide an improved circuit interrupter that provides improved performance.